022. Cardiac Rhythm Disturbances

SVT

Trick of the Trade: For valsalva maneuver, use a 10cc syringe and have the patient try to blow out the plunger. This is the equivalent of 40mmHg which is what you want to achieve with the valsalva.

For adenosine push, put the 6 or 12mg of adenosine in a 20cc syringe with normal saline. Then do a single push rather than using the stopcock. Just as effective, not diluted, its stable and goes to central circulation.

 

Atrial Fibrillation

Acute Decompensated Heart Failure with Afib: Is this new onset HF & AF? Is this chronic HF with new AF? Is this chronic HF & AF?

New HF and new AF: electrical cardioversion will likely work.

Vapotherm: high flow nasal cannula: giving PEEP without preload decrease you get with bipap.

Digoxin: treats AF and HF. 500mcg (8-12mcg/kg), peak onset isn’t until 30 minutes, full onset in 4 hours. 50% it works.

Vasopressors: Phenylephrine: pure alpha vasoconstriction. help augment BP was HR improved.

Diltiazem vs Metoprolol: 1.25-2.5mg every 2-5 minutes for metoprolol for AF + HF. If EF > 55%, ok to use both diltiazem (2.5mg per minute, max 25) with metoprolol. Use smaller doses at more quicker times between doses than the ‘large’ dose you usually give.

Amiodarone: If digoxin and metoprolol not working, start 150mg load, up to 300mg; after that, try to cardiovert them. Increases effectiveness of successful cardioversion.

Magnesium: vasodilator but can be used. Also give calcium.

Cardioversion probably faster/more successful than medications. Ibutilide and procainamide if going to use medications. Need to be under 48 hours from onset. Consider looking at ABCD2 score prior to discharge for anticoagulation. Ventricular rate control makes cardioversion worse. (AAEM Blog, 2017)

References

Trick of the Trade: Supraventricular Tachycardia, Michelle Lin, Essentials of EM 2014

Hypotensive Rapid A. Fib with Acute Heart Failure, Semhar Tewelde, The Crashing Patient Conference 2015

022. Cardiac Rhythm Disturbances

018. Cerebral Resuscitation and Therapeutic Hypothermia

How Cooling May Help: decrease inflammatory cascade, aborts cell death, reducing free radicals, decreases cerebral metabolism.

Therapeutic Hypothermia:

Tx of Comatose Survivors of Out-of-Hospital Cardiac Arrest with Induced Hypothermia; Bernard trial. 77 pts only; only v-fib arrest. Normal vs keeping less than 33C. Absolute mortality beneift of 16%. 23% absolute difference in patients with ‘good’ outcome.

HACA Trial – 275 pts; Normal vs less than 33C. Absolute benefit of 14% mortality, 16% absolute difference in patients with ‘favorable’ outcome. 1/10 NNT.

Mild Therapeutic Hypothermia to Improve the Neurologic Outcome after Cardiac Arrest, Nielson. TTM Trial – 939 pts (most vfib/vtach), keep above 33C and the other was below 36C. No control. No statistical differnce between 33 vs 36 for mortality/neuro outcome.

Contraindications: Rapid and complete recovery (patient following commands), illneses that preclude meaningful recovery (comfort care); DNR orders. Minor: know presence of cold agglutinins; Active or high risk of bleeding; > 12 hours after cardiac arrest.

Induction: Cold IVF, Surface cooling methods (Artic sun, cooling blanket). Endovascular regulation more precise and faster.

Shivering: increases systemic metabolic demand. Tx: skin counter-warming; magnesium (4g IV); sedation (versed/propofol/fentanyl), consider buspar with precedex. Last resort paralysis.

Phases of TH: Immediate cooling, maintain and monitor, then rewarm at 0.2C/hr and get into normothermia avoiding fever.

References

Resuscitation Following Cardiac Arrest, Christina Tupe, The Crashing Patient Conference 2015. http://cloud.emedhome.com/cme/cme_45768_hi.mp4?iframe=true&width=920&height=470

018. Cerebral Resuscitation and Therapeutic Hypothermia